The present invention is most generically directed on binaural hearing device systems which necessitate a communication link between a device arranged in or a adjacent one ear and a device in or adjacent the other ear of an individual. The one-ear device comprises at least an arrangement of input acoustical/mechanical converters whereas the other ear device at least comprises an output electrical/mechanical converter.
From the WO 99/43185 such a binaural hearing device system is known, whereat each device associated to an ear comprises an input acoustical/electrical converter and an output electrical/mechanical converter. There is further provided a communication link between the two devices whereby data or signals are cross communicated via such link which are respectively dependent from the output signals of the respectively provided acoustical/electrical input converters. Thereby before the respective converter output signals are applied to the communication link they are analogue/digital converted whereby there may be implemented in the respective analogue/digital converters some additional signal preprocessing.
Today's monaural hearing devices customarily have at least two input acoustical/electrical converters for beamforming purposes. The binaural system according to the WO 99/43185 may be tailored to provide beamforming by using the two input converters provided at the respective one ear attributed devices. Thereby, as outlined above, data are cross-transmitted via the communication link which are possibly preprocessed but which comprise substantially more information than really needed. Further beamforming with two input converters placed one on each side of individuals head may be quite complex and inaccurate e.g. due to the head-related acoustical transfer functions HRTF which describe the effects of acoustical signals being “shadowed” by individuals head. Such shadowing occurs, dependent on direction of arrival of acoustical signals, asymmetrically with respect to both ears which on one hand allows spatial perception, on the other hand renders beamforming quite complex.